Roof structure

ABSTRACT

A roof structure has its front and back edge supported by two series of linked truss members which form two arches anchored to the surface to be covered at their bases and sloping upwardly from the surface and outwardly in opposite directions. A number of flexible roof panels are attached between a centrally disposed ring member and the individual truss members of each series to provide the roof covering. Additional means are provided to raise the constituent parts of the roof structure to their operative positions and to maintain the structure in such position.

United States Patent 1 [111 3,906,685 Howard Sept. 23, 1975 [54] ROOFSTRUCTURE OTHER PUBLICATIONS [75] Inventor: Peter Howard, New York, N.Y.

, Construction Methods and Equipment, March, 1957, [73] Assignee: lmeroFlorentino Associates, Inc., pp 170 171 New York, N.Y.

[22] Filed: Jan. 30, 1975 [52] US. Cl. 52/63; 52/82; 52/83; 135/1 D [51]Int. Cl. E04B 1/12 [58] Field of Search 52/83, 82, 745, 63; 135/1 D, 2,3 C, 4 B

[56] References Cited UNITED STATES PATENTS 2,527,729 10/1950 Hoff 135/1D 3,028,706 4/1962 Falconer 52/83 3,149,703 4/1964 De Felice... 52/7453,153,302 10/1964 Wheeler 52/82 3,215,153 8/1963 Haddle 52/80 3,252,4695/1966 Peake 52/80 3,422,883 1/1969 Daltry 52/83 3,546,831 12/1970 Romo52/83 Primary ExaminerErnest R. Purser Assistant ExaminerHenry RaduazoAttorney, Agent, or FirmHopgood, Calimafde, Kalil, Blaustein & Lieberman[57] ABSTRACT A roof structure has its front and back edge supported bytwo series of linked truss members which form two arches anchored to thesurface to be covered at their bases and sloping upwardly from thesurface and outwardly in opposite directions. A number of flexible roofpanels are attached between a centrally disposed ring member and theindividual truss members of each series to provide the roof covering.Additional means are provided to raise the constituent parts of the roofstructure to their operative positions and to maintain the structure insuch position.

12 Claims, 10 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of 6 USPatent Sept. 23,1975 Sheet 3 of6 3,906,685

| I I Hunk- FIG.3

m El US Patent Sept. 23,1975 Sheet4 0.1 6 3,906,685

US Patent Sept. 23,1975 Sheet 5 of6 3,906,685

US Patent Sept. 23,1975 Sheet 6 of6 3,906,685

FIG9

ROOFSTRUCTURE BACKGROUND OF THE INVENTION A large number of shows andmusical events are now staged in stadiums and open amphitheaters becauseof the large seating capacities and ready availabilities of suchfacilities in many sections of the country. Most of these stadiums andamphitheaters are open to the elements at least in the central areawhere performers would normally be located for a concert or show, sothat they can be seen from a maximum number of seats. It is, therefore,necessary to provide a roof structure over the performing area toprovide protection from the weather for the performers as well as toavoid damage to expensive props and instruments. Since stadiums andamphitheaters are customarily utilized for sporting events and onlyoccasionally for concerts and shows, any roof structure must be of atemporary nature and should be easily and quickly set up and removableafter a few days or a few performances. Since, in order to performbefore differing audiences, performers customarily travel extensivelyaround the country and around the world, it is necessary to constructand take down such a roof structure many times at many different placesin the course of each tour.

Customarily, the necessary roof structure will be constructed out ofscaffolding by a company located in the area of the planned performanceon a custom basis. Such construction requires the use of cranes whichmust be anchored to the playing surface of the stadium to insure safeoperation and the placement of a large number of columns which areutilized to support sections of a canvas roof and which usually extendto the playing surface. Since the playing surface of modern stadiums isoften covered with an artificial grasslil e covering rather than grassthe driving of any stakes or the mounting of any support structure whichwould pierce this covering can cause expensive and lasting damage.

In addition, the building of a roof structure on a custom basis in eachlocation where a show is to be staged is expensive and the roofstructure built will be'of varying quality and will provide varyingconditions for the performance. It would be desirable to have a roofstructure which could be conveniently transported from place to place,both to decrease expense and to insure uniformly good performanceconditions at each location. It is not, however, possible for a touringshow to take the scaffolding of prior art roof structures from' place toplace because of the large number of separate pieces involved in suchstructures and the resulting complexity in reconstructing the structureat each location.

The present invention solves the above described problems of prior artstructures-by providing a roof structure which is portable and which canbe raised and supported by a single central support tower. Utilizing thenovel roof structure described herein results in savings in both timeand money during set up and removal of the structure and savesadditional money by avoiding the need for extensive custom constructionat each performance location. Since the roof structure is portable thesame structure may be used for each performance during the tour and theperformers can be assured of a uniform esthetically pleasing performanceenvironment in each location.

SUMMARY OF THE INVENTION A roof structure for covering at least aportion of a surface includes a plurality of truss members linkedtogether end to end to form two series of linked truss members which arearrangeable on the surface to form a substantially regular polygon aboutan axis passing through the surface when in a first unerected position;hinge means to anchor each end of each of said series of truss membersto the surface; a ring arranged within and substantially coaxially withthe polygon formed by the truss members; a plurality of flexible roofpanels each of which is connected along one side to the ring member andalong the opposite side to one of the truss members. First means areprovided to raise the ring member to a predetermined height abovethesurface and to support the ring member at said predetermined height, andsecond means are provided to raise-each of the truss members of said twoseries of truss members from said unerected position to a predeterminederected position above the surface and to maintain said truss members insaid erected position so that each of said series of linked trussmembers forms an arch which arch slopes upward from said surface andoutward from said axis from the bases to the apex.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the roofstructure in erected position.

FIG. I!) is a top schematic view of the arrangement of the linked seriesof truss sections of the roof structure prior to erection. I

FIG. 2 is a front elevational view of the roof structure in the erectedposition.

FIG. 3 is a side elevational view of the roof structure in the erectedposition.

FIG. 4 is a side elevational view of the roof structure in itsnonerccted position.

FIG. 5 is a partial top plan view of the support tower for the roofstructure taken along plane 5-5 of FIG. 2.

FIG. 6 is a perspective view of the anchoring means for the roofstructure.

FIG. 7 is a detailed view taken along plane 7-7 in FIG. 2.

' FIG. 8 is an exploded detailed view of the truss linking means shownin FIG. 7. I

FIG. 9 is a side elevational view of the roof structure with the roofpanels removed.

DESCRIPTION OF THE INVENTION The inventive roof structure 10 is shownfrom the front in FIG. 2. The roof structure 10 is mounted on a raisedplatform 12 having a horizontal surface 11 so that it covers a stagesurface 14 which is supported on surface II. A support tower 16 which isconstructed in accordance with known techniques is arranged at thecenter of the stage 14 on the surface 11 of platform 12 to providesupport for roof structure 10 as will be discussed more fully below.

The roof structure 10 includes a number of truss members 18 which areflexibly attached end to end to form two linked series of trusses 50 and72. The individual trusses 18 may consist of three main pipe members 20,21, 22, as best seen in FIG. 7 which are arranged in a triangularconfiguration with a number of smaller diameter cross pipe members 24arranged to provide strength to the triangular truss in a manner wellknown in the art. Each truss 18 is terminated by an end plate 26 as bestseen in FIG. 8 to which the main triangularly arranged pipe members 20,21 and 22 of the truss are attached. The trusses 18 are then joined toeach other end to end by a clevis and tongue joint as best seen in FIG.8.

The joint 30 includes a first arched shaped tongue member 32 having anaperture 33 which is mounted on and extends outwardly from a centralportion of end plate 260. Two additional similar tongue members 34 and36 are mounted on end plate 26b so that they are substantially parallelto each other and extend outwardly from plate 26b. Members 34 and 36include respectively apertures and 37 which are substantially aligned sothat the members 34 and 36 form a clcvis end adopted to mate with tonguemember 32. Tongue member 32 is inserted between members 34 and 36 andits aperture 33 is aligned with apertures 35 and 37. A bolt 38 isinserted through apertures 35. 33 and 37 and is secured by bolt 40 toformjoint 30 which is rotatable about an axis through bolt 38.

The trusses 51, 56, 66 and 71, which are located at each end of each ofthe two series of trusses 50 and 72, are attached to the supportplatform 12 by mounting plates such as 60 and 64 and a coupling 41 asbest shown in FlG. 6. Mounting plates 60 and 64 are attached to platform12 by bolts extending through aper turcs such as 6a and 60b in FIG. 6.The coupling 41 includes a cylindrical collar 42 which is spaced fromplate 60 by legs 43. A cylindrical rod 44 extends through and is rotablysupported at approximately its midpoint by collar 42. The inner radiusof collar 42 is preferably slightly larger than the outer radius of rod44 so that rod 44 may be rotated within collar 42. A

tounge member 45 having an aperture 46 is mounted at one end of rod 44while a clcvis end consisting of tongue members 47 and 48 is attached tothe opposite end of rod 44. Tongue members 47 and 48 include alignedapertures 47:1 and 48a. The tongue member 45 is attached to the clcvisend of a truss such as 51 while the clcvis end 49 of coupling 41 isattached to the tongue end of a truss member such as 56 in the mannerdescribed above. After attachment of these end trusses the rod 44 ofcoupling 41 is rotated through an angle of approximately 90 as theroofstructure is raised into its operational position as furtherdescribed below.

As is seen in FIG. 1. the roof structure of the present inventionincludes a total'of 12 truss members of the type described above whichare divided into two linked series 50 and 72 of six trusses each. Ifdesired each series of linked trusses could include more or less trussesthan the six shown for illustration. Each series of six trusses forms asupport structure for one side of the roof structure 10. The firstseries of trusses designated 50 in FIG. 1 includes trusses 51, 52, 53,54. and 56 which support the forward edge of roof structure 10 of FIGS.1 and 2. Plates and 64 are mounted on opposite sides of platform 12aligned with and spaced from the lateral sides of support tower 16.Plates 60 and 64 are used to anchor each of the ends of each of thelinked series of trusses to platform 12. The end plates 26 of trusses51, 52, 53. 54, S5 and 56 are linked end to end by clcvis and tonguejoints 30 as described above. A first end 58 of truss 51 is attached toplate 60 by a hinge coupling 41 which coupling is arranged as describedabove. Finally, the end 62 of truss 56 is attached to plate 64 on theopposite side of the platform from plate 60 by a similar hinge coupling41. Both ends of the linked series of trusses 50 are thereby anchored toplatform 12. An identical arrangement is used to link trusses 66, 67,68, 69, and 71 together to form a second series of trusses 72 whichsupports the rear side of roof structure 10. Again the free end of thefirst and last truss of the series, which in this case are trusses 66and 71, are attached respectively to plates 60 and 64. As illustrated.properly configured plates 60 and 64 can be used to anchor hingejoints41 to accommodate end 74 of truss 66 and end 76 of truss 71 so that twomounting plates 60 and 64 may be used to anchor both sides of trussseries 50 and 72 to the platform 12. If desired, separate plates can beused to anchor each end of each series of trusses.

The centrally arranged support tower 16 includes a number of pulleysmounted near the top as best seen in FIG. 5. FIG. 5 shows one halfof thepulley arrangement on tower 16 which also includes the same arrangementon the other side. Two pulleys 78 and 80 in FIG. 5 are located on thecorners of the support tower at a first level and are mounted on supportmembers 79 and 81 which are oriented in the direction of the corners ofthe support platform. Other pulleys 82. 84, 86, 88 and 90 are mounted ata second higher level on tower 16 and are supported respectively bysupport members 83, 85, 87. 89 and 91 which extend radially outwardlyfrom the central axis of the support structure.

A ring shaped member 92 having a central aperture configured to fitaround the support tower 16 and be slidablc vertically on the tower isshown in its raised position in FIGS. 1b and 2. The smaller end of anumber of substantially triangular roof panels 94, 96, 98, 100, 102 and104, which are preferably made of a flexible covering material such asvinyl or canvas, have their smaller apex ends attached about theperiphery of ring 92 by any convenient fastening means. lf desired. suchfastening means may comprise snaps or removable rings so that the roofpanels may be easily removed for storage. The larger base ends of eachof these roof panels is attached to one of the truss members 51 through55 or 66 through 71. Again. if desired, bases ofthc panels may beattached to the trusses by snaps or other means which would facilitateremoval of the panels for storage. Adjacent panels. such as 96 and 98 asseen in FIG. 1,.arc configured so that their adjacent sides overlap toprovide a continuous roof. For this same reason panels such as 94 and104 which form the two ends of roof half 72 are configured so that theyare larger than the other roof panels and extend a little more than halfway across plates 60 and 64 to the adjacent roof panels which areattached to the trusses comprising truss series 50 and which are notshown in FIG. 1.

The manner in which the roof structure is assembled and mounted over thestage 14 will now be described with reference to the above describedparts. The rect angular supporting platform 12 is first constructed bymeans well known in the art. The support tower 16 is then firmlyanchored to the center of the platform 12. Central tower guide cables106., 1 08, and 112 are connected from the upper corners of thesubstantially square tower 16 to the nearest corner of rectangularplatform 16. These cables are preferably attached to platform 12 throughturnbucklcs 114, 116., 118 and 120 to permit the tension of each of thetower guide cables to be adjusted to insure that the central tower 16 isproperly positioned and firmly anchored on the platform 12.

The trusses 18 are then arranged on thesurface of i the platform and areconnected to each other by clevis and tongue joints 30 and the first andlast end of each series of trusses, such as ends 51 and 56 of series 50in FIG. 1 are attached respectively. to plates 60. and 64 by a coupling41 as shown in FIG. 6. FIG. 1b shows the schematic arrangement of trussseries 50 and 72,after link-ing the individual trusses and attachmentofthe Y linked series of trusses to plates 60 and 64 by coupling members41. prior to raising the two sides of the roof structureto theiroperative positions in a manner to be described below. The individualtruss sections form a substantially regular polygon when linked andattached to platform 12 which in this case has twelve sides with a breakbetween the two linked series formed by plates 60 and 64. The regularpolygon approximates a circle having its center at the central axis oftower 16. In the illustration shown, 12 identical triangular trusses l7feet 6 inches-in length have. been usedand the radius of the circleapproximated by the resulting polygon is "35 feet. The distance betweenplates 60 and 64 is-approximately 70 feet which is, therefore, thedistance spanned by the roof structure 10. as illustrated. Longerdistances can be spanned by roof. structures in accordance with thisinvention if more or longertruss members 18 are utilized in each seriesof linked truss members. Utilizing a roof structure of the abovedimensions, a platform sixth feetin depth can be covered in its centralarea, as best shown in FIG. 1, which illustrates the "roof structure 10in its erected operative position.

members in each of the seriesof linked truss members 50 and 72. Each ofthese cables runs over one of the upper level pulleys such as 82, 86, 88and 90' of FIG. 5 and thence down, into the central tower 16 where theyare attached to suitable hoisting means such as winches .whichare notshown but are well known in the art. The suspension cable arrangementfor the truss members would be as follows for some of the truss membersshown. Cable 122 would pass over pulley 82. Cable 123 would pass overpulley 84. Cable 124 would pass over pulley 86.This arrangement would becontin ued around both sides of the central support tower 16,

so that eachof the truss suspensioncables would pass over a pulley totensioning means within the tower 16.

Tent ring suspension cables 136 through 139 are attached to four pointsspaced substantially summetrically about the tent ring 92. These tentring suspension cables pass respectively over the pulleys on the lowerlevel of 1G. 5 two of which are shown as 78 and 80 and two of which aresimilarly arranged on the side of the tower 16 which is not shown inFIG. 5. As in the case of the truss suspension cables after passing overthe pulleys 78 and 80 the tent ring suspension cables are attached totensioning means such as winches within tower 16 which are not shown.

The tent ring and the trusses are then pulled upward from the platform12 -by applying tension. to the truss suspension and tent ringsuspension cables/By this means the tent ring 92 is raised to theposition shown in FIG. 2 carrying with it the smaller apex ends of eachof the roof panels such as 104. 102 and in FIG. 3, and truss memberssuch as 54, 55, 56, 69, 70 and 71 as seen in'FlG. 3 are raisedfrom theposition of FIG. lb to their operative positions as seen in FIGS. la, 2and 3. FIG. 4 shows truss members 54, 55 and 56 immediately prior toraising them to their operative positions with truss suspension cables124, and 126 attached. Once in their operative positions the trussmembers making up the linked series of truss members 50 and 72 formarches which are anchored at their bases oneach side to plates 60 and 64and slope respectively upward and outward toward the forward and backedge of the platform 12 so that roof structure 10 covers as much of thecentral area of platform 12 as possible to provide a large unobstructedviewing area at both the front and back of the platform 12. therebyproviding an extensive usable performance area for the stage 14 as bestseen in FIG. 2.

To provide increased stability against wind forces additional trussguide wires and 151 are attached between joints 160, 161, 163, 164,165,166, 168 and 169 and the platform 12. Each of the truss guide wiresis preferably attached to the platform 12 through a turnbuckle such as170 through 181 so that the tension on each truss guide wire isadjustable to provide proper stability and positioning of the trusssections which make up the linked truss series 50 and 72. The additionalsupport afforded by the truss guide wires will now be discussed indetail with reference to joints and 161. Guide wires 142 and 141 areattached to joint 160 to form two sidesof a triangle with joint 160 atits apex. Guide wire 141 is also attached to one corner of rectangularplatform 12 and guide wire 142 is attached to a more central area of theside of platform 12. Junetion 161 is attached to guide wire 140 which isin turn attached to the corner of platform 12 at the same point ofattachment as guide wire 141. A similar arrangement is utilized tosupport junction 163 and 164; 165 and 166; and 168 and 169 as best seenin FIG. 1. No support structures extend across the large open areas atthe front and back of the stage so that the roof structure 10 providesunobstructed views of both the front and back portions of the stage.

As constructed in accordance with the embodiment described herein thesupport tower 16 extends 32 feet above the platform 12 and the apex atjoints 162 and 167 of the arches forming the sides of roof structure 10are nineteen feet above the level of the platform 12. The base of .thearches formed by the two seriesof linked trusses 50 and 72 join theplatform at an angle of approximately 33 /2 and the arches extendtransversely upward and outward at a substantially uniform angle of 33/2" from their bases at plates 60 and 64 to their apexes at joints 162and 167.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the inven tion and appended claims.

I claim: 1. A roof structure for coveringat least a portion of a supportsurface including a plurality of truss members;

linking means to join individual ones of said truss members end to endto form a first and a second series oflinked truss members, said seriesof linked truss members forming a polygon arranged substantiallysymetrically about an axis on said surface when said truss members arein an unerectcd position;

anchoring means to hold each end of each of said series of linked trussmembers to said support sur ,face;

a ring member arranged within and substantially coaxially with saidpolygon defined by said linked truss members in said unerected position;

a plurality of flexible panels having a first side connected to saidring member and the side opposite said first side connected to one ofsaid plurality of linked truss members;

first means to raise said ring member to a predetermined height abovesaid support surface; and

second means to raise said truss members in both of said linked seriesof truss members from said unerectcd position to an erected position atpredetermined heights above said support surface so that said first andsecond series of truss members from respectively a first and a secondarch, each of said arches sloping upwardly from said surface andoutwardly from said axis from the base to the apex of said arches.

2. A roof structure as claimed in claim I in which said linking meansincludes a plurality of clevis and tongue joints and in which saidanchoring means includes a roatable clevis and tongue joint.

3. A roof structure as claimed in claim 1, including cables extendingeach of said series of truss members and said support surface.

4. A roof structure as claimed in claim 1, in which said first meansincludes a first plurality of pulleys mounted at a first height abovesaid surface and a first plurality of suspension cables attached to saidring member, said suspension cables passing over said pulleys. and inwhich said second means includes a second plurality of pulleys mountedat a second height which is greater than than said first height abovesaid surface and a second plurality ofsuspension cables. said secondplurality of suspension cables being attached to points along each ofsaid series of linked truss members and each of said second series ofsuspension cables passing over one of said second plurality of pulleys.

5. A roof structure as claimed in claim 4, including means to applytension to said first and said second pluralities of suspension cablesto move said ring member to said predetermined height and said trussmembers to said erected position.

6. A roof structure as claimed in claim 1, in which the bases of each ofsaid arches join said surface at an angle of approximately 33.5".

7. A roof structure as claimed in claim 1, in which each of said archesextends upwardly from said surface at a substantialy uniform angle fromthe bases to the apex.

8. A roof structure for covering a portion of surface which structure isadopted to be supported by a single support tower arranged substantiallyalong an axis perpendicular to said surface;

a plurality of truss members;

linking means to join said truss members end to end to form a first andsecond series of linked truss members, said first and second series oflinked truss members forming respectively first and second arches, eachof said arches sloping upwardly from said surface and outwardly from aplane extending through said axis;

mounting means adjacent to said plane to anchor the bases of each ofsaid arches;

a ring member arranged coaxially about said tower at a predeterminedheight above said surface;

a plurality of flexible panels each having a first side connected tosaid ring member and a second side opposite said first side connected toone of said truss members;

first support means to hold said ring member at said predeterminedheight; and

second support means adopted to support each of said arches.

9. A roof structure as claimed in claim 8, in which said first supportmeans includes a first plurality of pulleys arranged about said tower ata first vertical distance above said surface and a plurality of Cables.each of said cables being attached to said ring member and extendingover one of said pulley, and in which said second support means includesa second pluralitly of pulleys arranged about said tower at a secondvertical distance above said surface. said second distance being greaterthan said first distance. and a second plurality of cables attachedrespectively to a plurality of points along said series oflinked trussmembers and extending respectively over one of said second plurality ofpulleys.

10. A roof structure as claimed in claim 10, including additional cablesextending respectively from said surface to points along said series oflinked truss members. and means to adjust the tension on each of saidadditional cables.

11. A roof structure as claimed in claim 8, in which said linking meansincludes a plurality of hinged couplings disposed between adjacent endsof said truss members making up each of said linked series of trussmembers. and said mounting means includes a rotatable hinged couplingconnecting the bases of each of said arches to said surface.

12. A roof structure as claimed in claim 11 in which said hingedcouplings are clevis and tongue joints.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.5.906.685 Dated September 25. 1975 Inventor(s) Peter H ward It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 7, line 56, "roatab le" should be rotatable.

Column 7, line 58, after "extending" insert -between-. Column 7, lineLI-7, after "greater" should be only one (1 "than".

Column 8, line i, "substantialy" should be --substantially--.

Bignzd and Sealed this sixteenth Day Of December 1975 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Patentsand Trademarks

1. A roof structure for covering at least a portion of a support surfaceincluding a plurality of truss members; linking means to join individualones of said truss members end to end to form a first and a secondseries of linked truss members, said series of linked truss membersforming a polygon arranged substantially symetrically about an axis onsaid surface when said truss members are in an unerected position;anchoring means to hold each end of each of said series of linked trussmembers to said support surface; a ring member arranged within andsubstantially coaxially with said polygon defined by said linked trussmembers in said unerected position; a plurality of flexible panelshaving a first side connected to said ring member and the side oppositesaid first side connected to one of said plurality of linked trussmembers; first means to raise said ring member to a predetermined heightabove said support surface; and second means to raise said truss membersin both of said linked series of truss members from said unerectedposition to an erected position at predetermined heights above saidsupport surface so that said first and second series of truss membersfrom respectively a first and a second arch, each of said arches slopingupwardly from said surface and outwardly from said axis from the base tothe apex of said arches.
 2. A roof structure as claimed in claim 1 inwhich said linking means includes a plurality of clevis and tonguejoints and in which said anchoring means includes a roatable clevis andtongue joint.
 3. A roof structure as claimed in claim 1, includingcables extending each of said series of truss members and said supportsurface.
 4. A roof structure as claimed in claim 1, in which said firstmeans includes a first plurality of pulleys mounted at a first heightabove Said surface and a first plurality of suspension cables attachedto said ring member, said suspension cables passing over said pulleys,and in which said second means includes a second plurality of pulleysmounted at a second height which is greater than than said first heightabove said surface and a second plurality of suspension cables, saidsecond plurality of suspension cables being attached to points alongeach of said series of linked truss members and each of said secondseries of suspension cables passing over one of said second plurality ofpulleys.
 5. A roof structure as claimed in claim 4, including means toapply tension to said first and said second pluralities of suspensioncables to move said ring member to said predetermined height and saidtruss members to said erected position.
 6. A roof structure as claimedin claim 1, in which the bases of each of said arches join said surfaceat an angle of approximately 33.5*.
 7. A roof structure as claimed inclaim 1, in which each of said arches extends upwardly from said surfaceat a substantialy uniform angle from the bases to the apex.
 8. A roofstructure for covering a portion of surface which structure is adoptedto be supported by a single support tower arranged substantially alongan axis perpendicular to said surface; a plurality of truss members;linking means to join said truss members end to end to form a first andsecond series of linked truss members, said first and second series oflinked truss members forming respectively first and second arches, eachof said arches sloping upwardly from said surface and outwardly from aplane extending through said axis; mounting means adjacent to said planeto anchor the bases of each of said arches; a ring member arrangedcoaxially about said tower at a predetermined height above said surface;a plurality of flexible panels each having a first side connected tosaid ring member and a second side opposite said first side connected toone of said truss members; first support means to hold said ring memberat said predetermined height; and second support means adopted tosupport each of said arches.
 9. A roof structure as claimed in claim 8,in which said first support means includes a first plurality of pulleysarranged about said tower at a first vertical distance above saidsurface and a plurality of cables, each of said cables being attached tosaid ring member and extending over one of said pulley, and in whichsaid second support means includes a second pluralitly of pulleysarranged about said tower at a second vertical distance above saidsurface, said second distance being greater than said first distance,and a second plurality of cables attached respectively to a plurality ofpoints along said series of linked truss members and extendingrespectively over one of said second plurality of pulleys.
 10. A roofstructure as claimed in claim 10, including additional cables extendingrespectively from said surface to points along said series of linkedtruss members, and means to adjust the tension on each of saidadditional cables.
 11. A roof structure as claimed in claim 8, in whichsaid linking means includes a plurality of hinged couplings disposedbetween adjacent ends of said truss members making up each of saidlinked series of truss members, and said mounting means includes arotatable hinged coupling connecting the bases of each of said arches tosaid surface.
 12. A roof structure as claimed in claim 11 in which saidhinged couplings are clevis and tongue joints.